Process for the treatment of sulfid ores.



"no. 843,986. PATENTED FEB. 12, 1907.

H. BAKER & A. T. SMITH. PROCESS FOR THE TREATMENT 0 SULFID 0115s.

APPLICATION FILED JUNE 22, 1906.

3 SHEETS-SHEET 1- WITNESSES.

No. 843,986. PATENTED FEB. 12, 1907.

H. BAKER & A. T. SMITH.

PROCESS FOR THE TREATMENT OF SULFID ORBS.

APPLICATION FILEDJUNE 22, 1906.

3 SHEETS-SHEET 2.

Fly 2.

J Iv

"TIW

W/TA/ESS'S. //1// A/70Rs No. 843,986. PATENTED FEB. 12, 1907.

H. BAKER & A. '1'. SMITH.

PROCESS FOR THE TREATMENT OF SULPID ORES.

' APPLICATION FILED JUNE 22, 1906.

3 SHEETS-SHEET 3.

UNITED STATES PATENT oEEIoE.

HARRY BAKER AND ANDREW THOMAS SMITH, OF WESTON POINT,

' ENGLAND.

, PROCESS FOR THE TREATMENT OF SULFID ones.

Specification of Letters Patent.

Patented Feb. 12, 1907.

. Ap lication filed June 22,1906. Serial No. 322.369.

ton Point, Cheshire, England, have invented anew and useful Im roved Process for the Treatment of Sulfid res, of which the following is a specification.

Among other processes it has heretofore been proposed to treat complex sulfid ores with aqueous solutions of cupric chlorid and sodium chlorid or calcium chlorid and as. an entirely subsequent and separate operation,

' and after treating the liquor obtained above to' free it from metals acquired from the ore to reconvert the cuprous chlorid into cupric chlorid'by an intricate atmospheric oxidation-and preci itation method. It has also been propose to use aqueous solutions of ferric chlorid, and as an entirely subsequent and separate operation and after treating with iron or'zinc. the liquor obtained above to free it from metals or some of them acuired from the ore to reconvert the ferrous iiblorid into ferric chlorid by treatment with f chlorin or otherwise. It has further been proposed to employ. aqiueous. solutions of salt or magnesium chlori and chlorin.

The present invention relates to certain im rovements 'in those known processes.

, riefly stated, the nature of the invention ma be described as consisting in treatin suc ores while in a fine state of division anc While suitably agitated t0 the apparent action of chlorln, but in such a way/that the chlorin before it reaches the ore or the sulfur liberated from the ore in the preceding mo- -ments is absorbed by the-ferrous or cuprous chlorids present and is thereb converted into ferric or cupric chlorids. hese higher .chlorids, it is well known, will react on the furtherportions of the ore and are thusrapidly exhausted, being reconverted into inert ferrous and cuprous chlorids; but it is of the essence of this invention that small uanti ties of ferrous and cuprous chlorids a mixed with the chlorids or any other metals obtained' from the ore should by their oft-re- I quantities of iron and copper, so that the. v

peated chlorination change, to the higher chlorids, and thus act as chlorin-carriers to the whole of-the' chloridizable material in the ore as zinc, lead, maganese, and still further ratio of either iron or copper, to sa zinc, is no more in the final liquor obtaine than it is in the ore itself.

Further, it is of the essence of this invention that no other extraneous materialsas sodium chlorid, calcium chlorid, magnesium chlorid which would interfere with the recovery of the zinc of the ore in the form of pure zinc chlorid are introduced, and also that the absor tion of the chlorin is so effected that the iberated sulfur, which toward the end of the run comes to the surface in the form of a, foam, is not brought into contact with chlorin gas, whereby chlorid of sulfur and its decomposition products would be formed and also that the said foam of crude sulfur may be removed in any convenient way.

If the ore treated was a pure sulfid of zinc, the chlorid of zinc produced by the process described could then be readily separated from the accompanying iron chlorid and the pure zinc chloric converted. to a metallic state, setting free the chlorin, which could be employed for converting ferrous chlorid into ferric chlorid, but the complex ores to the treatment of which this invention ismainly directed usually also contain lead sulfid, and while this will'be converted into a lead c'hlorid the latter is only soluble in water to a very limited extent. insoluble in the solution and to separate it from the zincmetallic iron is added, which metal, having a greater afiinity for chlorin than the lead, combines with the chlorin, forming ferrous chlorid, while the lead is thrown down in a metallic state, in which To render such lead form it may be readily separated from the rate these metals it will onlybe necessary to ,reconvert theminto the chlorid saltsin -the presence of but little water, in which, while the copper salt is readily soluble, the lead saltis not and maybe separated byfiltr'ation, when the metals may be again but separately thrown down by adding iron to their ,solu

tions andtothe sludge, while the chlorid of iron so prdduced may be converted into T ferric chlorid,'and to this oxid of zinc may be added, thus producingia chlorid of zinc and iron oxid.

If silver be present in the ore, it will separate from the zinc in a manner analogous to that of lead, which it will follow and from which it may be separated by the usual known means. Gold also, if present,

and with a little care may be caused to follow and separate out either with the lead and silveror with the copper, from either of which it may be separated by the known methods.

For practical manufacture or se' aration of the metals it is pro osed that for t e initial charge the finely-divlded ore be added to a quantity of water and be thorou hly agitated therein until the ore is practical y suspended in the liquid; but in all succeeding charges we may use a portion of the liquor from a preceding charge, with or without an intermediate purification and (or) the various washwaters and water to make u the necessary quantity, and the turbid liquld is then treated with chlorin in the form of ferric orlike chlorid, so as to insure that practically no free chlorin is 'resent. The proportions should .be such t at there is presenta suitable amountof both a lower and a higher chlori'd of such a metal as iron, one of the chloride of which iscapable of acting as .an energetic absorber of chlorin and the other as an energetic agent for attacking metallic sulfids, so as to produce as new products the chlorid of the metallic sulfid attacked and free sulfur- The reason for thus controlling and to the possible loss of sulfur if the sulfuric acid has to be removed by' recipitation as useless calcium sulfate. urther, sulf'uric acid in the presence of lead ores may coat the particles of such ore with a coherent coating that tends to protect them from the further action of the solvent or corrosive liquid. The object of using a proportion of liquor from a revious char e is to have present from this moment of startin the treatment with chlorin gas a sufficient c arge of ferrous chlorid to absorb the chlorin as fast as it can be supplied, thus producing ferric chlorid, which in turn parts with one atom of its chlorin to the metals in the ore and again becoming ferrous chlorid and being again reconverted to ferric chlorid, and so on, and, secondly, the object is to have a liquor present with an increased viscosity and specific ravity, so as to aid in suspendin and distributing the powdered ore and to eeaese metallic-sulfid ores, and therefore there is generally no necessity. to add any extraneous iron to start the initial operation, though this may be done, if desired, by adding a portion of an iron-sulfid ore or a portion of ferrous chlorid solution known as galvanizers waste pickle, 620.; but such additions should not be made in larger quantity than is really necessary, because the excess of iron may be somewhat inconvenient in the after treatment. In subsequent operations there is always an ample supply of chlorin absorbent present. Without binding ourselves to any particular quantity we may say that we have found the presence of the equivalent of two grams of metallic iron per liter of liquor to be quite sufficient to absorb chlorin at a rate which is commercially quite satisfactory, and also in a very com )lete manner from such chlorin as is manu actured on a large scale without unusual precautions. In all the preceding it is distinctly explained that the chlorin is not used itself to attack the sulfid ore, but that ferric chlorid or the like body is used to attack the ore and that it is the one remnant of the ferric chlorid viz., the ferrous cli-loridthat is acted u on b the chlorin. The success of this met od of leaching will not solely depend on the use of ferrous and ferric chlorids as absorber and carrier of chlorin, as other features must be attended to, as hereinafter set forth. The necessity for agitating in gas-tight vessels during treatment is obviated by our invention, inasmuch as the chlorination of the ore is effected by ferric chlorid and the reduced ferric chlorid is rechlorinated in a separate vessel. Bulky lead chlorid and a magma of sulfur are formed in the reaction, and the ore particles might thereby be screened from further action. We prevent this screening by leaching in vats with a quantityof liquor at least several times the weight of the ore and by keeping the contents of the vats strongly agitated, so thatthe particles are in motion or suspension the whole time. We assist the suspension of. these particles by working with strong solutions for example,

of speclfic gravity 1.2 to 1.5and, further, we assist the suspension by makin the particles themselves as small as possiblei. e., we grind the ore very finely, for example, until it all passes throu h a wire-gauze with six 'teen meshes to the mear inch, although we met 0d now described.

amass We judge that the following forms of apparatus, which are givenas practical examples, will be serviceable.

Referring to the drawings, Figures 1, 2, and 3 are mainly sectional elevations, of which Fig. 1 is first described. In this form the reaction vessel is a large stone tank of, say,'six hundred 'cubic feet capacity, such as is used for the generation of chlorin from manganese dioxid and hydrochloric acid. Through a central earthenware pi e B, dependent from the top stone, is passe a strong beam C, of suitable wood, as teak, or of stone or slate, suspended, guided, and driven from above and also so arranged that it may be raised or lowered a short distance at will in any convenient manner. This arrangement is of considerable importance, as with a given ore and given tank it is a most important factor in determining the amount of material that can be treated at one operation without the load of undecomposed ore or the insoluble residuals exerting too greata drag on the mechanical agitator, especially if the agitation is interrupted for any reason or accidentally. Upon this shaft 0' and inside the tank there is built up by dovetailing and wedges of the same materials a large stirrer D, that articularly agitates any heavy particles W ich settle on the bottom, and also stirs the whole contents of the tank. .The woodwork may be boiled in crude ozocerite linseed-oil, or similar inert protective and also may be coated with tar. The ferric chlorid attacks the wood but slowly, and though the bottom of the stirrer is subject to abrasion it is nevertheless easily replaced. An earthenware pipe E, also dependent from the top stone, is used for the introduction of supplies of liquor or ores or for the taking of samples, &c. The chlorin may be put under pressure b a pump and then made to bubble through t e turbid liquor; but we judge it preferable to absorb the chlorin in a small absorption-tower G, through which a portion of the turbid liquor is rapidly circulated, and to secure this we propose to place a hole F on one side of the tank and sufficiently below the working level of the liquor to insure that none of the liberated sulfur which floats up to the surface toward the end of the operation and there forms a thick scum enters the hole, and yet placed sufficiently above the bottom of the tank to insure that none of the heavier particles of undecomposed ore accumulated on or near the bottom enter the hole. Attached to this hole by a valve S and a ipe isa centrifugal pump T, which serves to aw the liquor and deliver it to the top of the absorption-toWer G. The valveipes and centrifugal may be made of earthenware or of ebonite; but metal of all kinds should be kept from contact with the highly corrosive liquor.

The valves, pipes, and centrifugal should be of suflicient dimensions and power to keep up a rapid and copious flow of liquor over the packing-pieces in the absorbingtower. By way of'example, the size of a suitable pipe and valve would probably be five inches diameter, and the centrifugal'proportionate to this. The importance of this copious flow arises from the fact that it is a main factor in determining the rate at which the ore can be treated and in preventing troubles and loss arising from the possible oxidation of part of the liberated sulfur. The absorption-tower G may be made of large earthenware pi es filled in the way usual with much sma ler and shorter ieces of earthenware pipe to break up an distribute the liquor and gas flow. Enterin the top of the absorption-tower is a second pipe H, controlled by a suitable valve or lute, (not shown,) which controls the admission of chlorin from any suitable source of sup ly. Under suitable working conditions which it is easy to obtain the absor tion of the chlorin is com lete, and the residual as may be allowe to enter the gas-space T liquor-level in the tank and then make its escape by any pipe properly controlled by a suitable valve or lute; but as the top of the liquor will frequently be covered with a froth of sulfur and as at the beginning and end of each "operation some chlorin may escape absorption it is better in order to avoid possible chlorination of the sulfur not to allow the residual ases to enter the space at the top of the tani, but to trap the bottom of the tower,by a pipe K, extending into the liquor, and to rovide an outlet L at the base of the tower t irough which opening almost the whole'of the residual gases may pass. The falling liquor in the tower exerts a powerful mechanical action on the gases in the tower and produces considerable drafts, which are utilized to draw the chlorin from the source of supply through H, and to force the residual gases out of t e apparatus. When a charge is approaching completion, it may be necessary to regulate or to stop the flow of chlorin. This may be done by regulation of the admission gas-valve in H. Toward the end of the chlorination liberated sulfur will begin to float up to the surface of the liquor, and still more will be liberated at a later sta e of the rocess, to be subsequently describe To collect and remove this sulfur scum as it is formed, or at convenient intervals, various means maybe employed. Thus the removal may be effected throughv an opened manhole M by manual labor with scoops and ladles, or bya mechanically-revolving series of chain-buckets that can be exactly raised or lowered to suit the position of the foam and liquor levels, or by means of a suction-nozzle of suitable shape dis.-

charging into 'a close reservoir in which a partial vacuum ismaintamed by an airpump, or through an opening in the side of above the described.

the tank well under" the liquor-level by a skimming-dish attached by a flexible rubber pipe of sufficient boreto the opening. The

skimming-dish may be regulated by the liquor-level in any suitable way.

The sulfur scum removed by any of the above methods may be pumped or blown into a filte'r pr'ess and the filtrate returned to the tank, the sulfur cakes being then washed, and the washings used in the next charge and the cakes of sulfur can then be purified or utilized in any desired way.

If preferred, the agitation of the ore may be effected not only by a heavy flow of the acting-liquor, but by an equal flow of air pumped under the surface of theliquor, and in this case of course a special air-pump wo'uldbe required, and in either case the tank would then preferably be of conical form 'say as shown in Fig. 2, although the horizontal section of the tank may be cylindrical or polygonal. With such construction the liquor is charged into the tank through a pipe E, and the liquid'leaving by opening F and thevalv'e S would be energetically forced again into the very bottom of the tank through a pipe K to be again circulated. in a similar manner. adding ore'through the charging-pipe 'E or the manhole M the falling particles would meet the rising current of liquor from the bottom and at some 'particular'point each particle would find a position about which it would remain suspended. A portion of the liquor driven by the centrifugal is allowed to flow by suitably opening a valve S into the top of the absorbing-tower G, where it absorbs the desired amount of chlorin and then returns into'the tank, the residuals from the crude chlorin gas escaping, all as before Instead of coupling the two circulating systems in this way the gas-absorbing'system may be driven by a separate liquor-pump, or, again, the two circulating systems maybe combined into one, in which case the tower and its connection-pipe must be so arranged that a sufficient ressurc is obtained in the pipe to effective y suspend the ore particles in the tank, or, again, while the liquor. is circulating through the tower and the pipes, as already described, the agitation of the liquor and ore may be effected or assisted by a strong current of air forced into the bottom of the tank. 7

Alternatively the tank may be more or less cylindrical in'shape, as shown'in Fig. 3, and caused to revolve on a horizontal axis. With such a construction one end of the cylinder would have an o ening for introducing liquids or solids an at the other end a larger opening F, preferably fitted with a curved mouthpiece for the outflow of liquid during the rotation, and in the cylindrical portion are one or more openings Q R, small and large, for the decanting of liquor or the ()n then I eaaaee removal of heavy sediments, the smaller holes preferably provided with suitable pouring-spouts and the larger holes solarge that a laborer could enter to shovel out the material all such a ertures and circum fer'ential openings being closed by suitable covers or plugs. A charge of liquor being run in and the rotation started, so much more liquor is added that it runs out of the other end by the mouthpiece Finto a tank N and thence by the centrifugalT is driven to the top of the chlorinating-tower G, and

from the bottom of this it returns through trapped pipe K to the cylinder ready to overflow with the circulating liquor into the small tank N, where suitable arrangements may be made to collect and remove the sulfur scum. v I U When using a fixed tank, as in Fig. 1, the

operation would be as follows: The tank would for the initial operation be charged withwater, preferably warm and, say,five hundred cubic feet. The stirrer D wouldbe lowered until the bladeis but, say, one to two inches from the bottom, andjthe agitation is begun by running the shaft Cat, say, twenty-five revolutions per minute. A quantity offinely-powdered ore, say one-half ton, in the form of wet mud or of dry powder is added. The centrifugal T is then started and the, valye S and that in H lifted, preferably only so' much that tests of thegas leaving through L show it to be .free or 'al'most free of chlorin.

lapse of an 'hour'or thereabout a further quantity of ore may be added and the chlorin-valve opened farther, but so as. still to obtain an almost complete absorption and also particularly so that no free chlorin is present in the liquor and as a perfectly safe guarantee of'thi's, so that the liquor contains.

a very perceptible portion of its total iron After the present in the form of ferrous chlorid. After i a few hours the liquor contains so much iron dissolved from the-ore that the chlorin can be taken up as fast as it can be supplied and yet all the above conditions be complied with.

Furthercharges of ore are then added, so as to make the total for the given quantity of water six tons or more, accordin to the quality of the ore. The liquor will t en-be found to contain a large art of its total dissolved iron in the form 0' ferrous chlorid; but this will slowly decrease, and when it becomes only a small part the admission of chlorin should be decreased and finally stopped; but the agitation should be continued to ascertain by any alteration in the ratio of ferrous to ferric iron if any residual ore remains andis being acted upon. Toward the latter end l of the operation the liberated sulfur begins to float up to the surface, forming a scum, which may be allowed to accumulate or may be removed at once, as already mentioned. The liquor in the early stages of the operation will probably be found to be neutral; but toward. the end it will probably be found to become somewhat acid, and before proceeding to the next. operation it is better to remove at least the greater part of this acidity by adding the necessary amount of an oxid ore, as zinc carbonate, copper carbonate,'lead carbonate, or any other suitable material and preferably in a very fine state of division.

" slime.

It will also simplify the next operation if the largest portion of the ferric chlorid necessarily contained in the solution is converted into ferrous chlorid by the addition of the necessary amount of a sulfid orefor exam- 'ple,some of the ori inal or'e-but this time in the condition of t e very finest powder or These treatments of the chlorinated liquor with regulated amounts of oxid ores 0r oxid materials and of sulfid ores are part of the present invention. We have said that the liquid used for the process described should preferablybe warm. This is for the purpose of accelerating the reaction, and the necessary temperature-say 50 centigrade may be obtained by injecting steam, and

preferably through arubber or ebonite tube. During the process of the reaction the temperaturerises naturally and may attain 80 centigrade, to which there is no objection. With very rich ores the temperature might become too great. It may be regulated by sucking air though the absorptiontube and blowing out the admixed hot air and steam. In fact, the higher the temperature up to the boiling-point the quicker the reaction of the higherchlorid upon the ore,

and consequently a better commercial yield is obtained, as all the zinc contents are converted into zinc chlorid. The progress of the reaction may also be watched by taking the s ecific gravity of the liquid portion of the s urry, and the end of the reaction is told by the specific gravity ceasing to rise, as well as by the ratio of ferrous to ferric chlorid, &c., already mentioned. It is to be understood that the ore may be added as described or continuouslyor in one portion at the beginningfbut in any case it is advisable after the last portion of ore has been added to con-- copper.

be so thrown down are lead, silver, copper, gold, bismuth, mercury, tin, &c., and they are thus readily separated from the remaining metallic constituents, as zinc, iron, manganese, nickel, cobalt, &c., and aluminium, calcium, &c. As complex sulfid ores containing zinc, lead, iron, manganese, silver, copper, and silicious gangue are of very frequent occurrence, we will describe ourinventionas applied to such an ore, by way of example; but our method is equally applicable to other ores not here specified. The second step consists, then, in addin to the slurry of. chlorids, prepared as alrea y described, the necessary quantity of metallic iron as to throw down the whole of the lead, silver, and The iron used for this purpose is preferably in a fine state of division. iron borings and turnings after grinding and sifting the same through a mesh of sixteen to the linear inch are suitable; but where sufficient of these cannot be obtained they may be well replaced by the very finely divided iron obtained by reducing an iron oxid ore by producer-gas or charcoal at a very moderate heat but where the revolver form of aparatus is used the iron may be used in the orm of scrap-sheet and with great advantage in the form of scrap galvanized sheet, tin, or terne plate, since the excess of iron is no detriment to the agitation, and the excess may be easily removed. In order to reduce the amount of metallic iron to be added, it has already been described how free acid may be removed, or nearl so, by addition of a suit able oxid and how erric chlorid may be removed, or nearly so, by addition of veryfinely divided sulfid ore. The reactions re uire more or less time, according to the size 0 the iron or zinc particles employed, and durin the whole time the agitation must be carrie on vi orously. The acid and the ferric chlori rapidly disappear and the lead in solution then begins to decrease, and the end of the reaction can be readily told by testin a small portion of the clear liquor for lead Ty potassium iodid. All the suspended crystals of lead chlorid are then converted into spongy lead. The completion of the reaction may be accelerated by the additionbf small further quantities of the powdered iron from time to time as found necessary by the tests. Tests may be applied for the completeness of the reci itation of the silver, gold, and copper; ut i the lead is completely Cast- 7 removed these other metals should also be but in such a manner as to separate as completely as possible the lighter portion consist ing, essentially, of finely-divided gangue from the much heavier part consisting, essentially, of metallic spongy lead and copper. To i keep the gangue suspended, the agitation must be continued, although it may be ad visablc to reduce the speed of rotation or to raise the stirrer somewhat'further from the bottom of the tank. The turbid liquor should not be drawn off from the bottom hole, but may be drawn off from one or other of a series of holes placed at different heights in the side of the tank, the highest hole being utilized first and the lowest hole last, regulating theaction of the stirrer meanwhile in the'm'anner already mentioned. When using the revolver form of tank, the rotation is stopped with the small hole Q above the liquor-level, and the valve attached thereto is opened, and by more or less slowly rotating so as to bring this opening just under the liquid level the lighter slurry may be poured ofi, While leaving the heavy metallic sponge behind in a very com lete manner. During this process the tan empties itseif. The opening is then closed, some of the clear filtrate is returned to the revolver, and the metallic sponge washed free from gangue, and then by water it is washed free from zinc, &c., chlorids. The revolver is then drained, the large manhole R opened, and conveniently placed so that the heavy metallic sponge may be removed. The turbid liquor is filt'ered by any suitable means. Then it may be received in a lead-lined montejus, and thence forced by air-pressure into wooden filterpresses, which when full are washed with water and the cakes removed to be further treated. To remove as much of the gangue as is possible from the spongy metals, some of the clear liquor from the presses is run back into the tank, the agitator run briskly and gradually lowered, then gradually raised and slowed again, and the turbid liquor run and filtered as before. This operation maybe repeated several times. The spongy metals may then be Washed with water several times in the same fashion-t0 free them from the soluble chlorids of zinc, iron, &c., and, lastly, they are drained in the tank. Instead of iron we may employ low-grade zinc for the reduction. It should be very finely granulated by pouring into water or by agitating the fused metal during solidification, or the shavings used in cyaniding may be used. The filtrate and washings contain zinc chlorid, ferrous chlorid, manganese chlorid, and proportionately very small quantities of sulfates of these metals and are to be worked up as subsequently described.

The heavy metallic residues contain lead, copper, silver, with proportionately very small quantities of gangue, sulfur, and undecomposed ore and excess of metallic iron.

are,

They may be treated by ordinary metallurgical process, or they may be still further treated as described subsequentl It is evident that the three soiid products already referred toviz., first, sulfur; second, gangue; third, metallic spongy lead, &c.- may be separately and again subjected to a similar or any suitable mechanical treatment to complete as much as possible the separation of these bodies from one another. The crude zinc-chlorid liquor is then treated-with chlorin and zinc oxid, when-the iron is precipitated as ferric oxidjand may be filtered off and washed, to be utilized as desired. The filtrate is then freed from manganese chlorid by a second treatment with chlorin and zinc oxid; but this time the liquors should be hot, and steam is therefore injected or the liquor is otherwise heated to about centigrade, when the manganese is precipitated as manganese dioxid and is filtered off and washed, to be utilized as desired. In place of precipitating the iron and manganese separately they may, if desired. be preci itated at one operation b heating and a ding a sufficiency of zinc oxid and continuing the treatment with chlorin until both are com letely removed. The zinc oxid referred to a ove need not be pure, but such residual materials containing only, say, twenty-percent. zinc oxid as are obtained in various metallurgical and other processes, or in place of zinc oxidmay be used zinc carbonatei. e., calamin. In any case the zinc-oxygen compound should be finely ground, and during the treatment of the mixture with chlorin the whole should be kept well agitated, and we most easily effect the absorption of the chlorin not by blowing the gas through the agitated slurry by pumps, but bythe use of an absorption tower and a centrifugal pump, just as described for the treatment of the original sulfid ore. Almost all such forms of zinc-oxygen compounds contain small or even large quantities of calcium compounds, and those react with the small quantity of sulfates contained in the crude zinc-chlorid liquor to form gypsum, the largest part of which is filtered off alon with the oXids of iron and manganese, and the purified zincchlorid liquor besides containing a very small quantity of gypsum in solution may contain small or large quantities of either calcium chlorid or zinc sulfate. The former is removed by adding the required amount of zinc sulfate, the latter by addin the required amount of calcium ,chlori which may be easily obtained byreci itating another charge of crude zinccl i lori( liquorwith a calamin containing a large proportion of lime, or by lime itself. Should, however, the amount of zinc sulfate be considered to be too large to remove it in such a way, it can be essentially removed by evaporat ng until the specific gravity of the solution rises to 1.5 or 1.6. when the zinc sulfate separates in fine utilizedin any way desired. The zinc-chlorid liquor prepared as already described may be rendered exceedingly pure by small further treatments, as is already known to those acquainted with such work, and the solution may be concentrated or evaporated to fusion and ma where there is a market for such materia s, be sold as such, or where it is desired to extract the zinc in the metallic form the solution or the fused material is electrolyzed to obtain metallic zinc of a very high degree of purity and gaseous chlorin, which can enter again its cycle of operations for attacking a further portion of complex sulfid ores in the ways described, so as to allow of the separation of the various valuable constituents of the ore.

The insoluble residue obtained on treating the sulfid ore with chlofin and then with, say,

metallic iron contains a small part of the gangue of the crude ore, ossibly a small art of the lead in the form 0 lead sulfate an the rest as metallic lead, all the co per, silver, and gold in the metallic form, an also a very smal portion of the sulfur which has been separated in the free form, and any small excess of metallic iron and undecomposed ore. To recover the copper and to decompose any small residual of undecomposed ore, the material placed in a suitable vessel, where it can 1 be agitated with water, is treated with chlorin gas, which gradually converts the metallic iron, lead, copper, and possibly silver and gold, and the undecomposed ore into chlorids, and by filtering this slurry there is obtained a quantity of solution containing all the copper, a very small portion of the lead, andpossibly traces of silver and gold, which clear solution may be treated by known methods.

The residue of lead chlorid with small quantitiesof gangue, sulfur, and lead sulfate may be again agitatedwith water and finelydivided metallic iron or even zinc-scrap to "recover the chlorin in a form which can be converted into pure zinc chlorid by the preceding processes and to convert the lead material into a form that is more readily smelted. These last two processes are best carried out, in stone or earthenware revolvers because'of the great specific gravity of the solids being treated and the relatively small amount of liquor with which it is desired to This process may be used for the treat- I ment of complex lead-zinc ore, such as that described, even when the metal contents are low. Copper may be used alone or in conjunction with iron as chlorin-carrier. Our process is also applicable to many other ores, such as those containing copper, tin, nickel, lead, and zinc. In such cases the treatment after conversion to chlorids is varied to suit the metals. For exam le, a copper-zinc-iron' ore-need not be treate with iron borings after chlorination. The gangue and sulfur are filtered out, and the copper-zinc solution is purified and the metals separated by fractional electrolysis, or the copper may be deposited by metallic zinc. In this case the finely-divided metals alloy to some extent, and the copper finally contains a little zinc, an impurity much less hurtful than the iron in ordinary cement co per.

Havin now particu arly described and ascertaine the nature of our said invention and in what manner the same is to be performed, we declare that what we claim is- 1. The process of treating sulfid ores which consists in submitting the ores to the action of chlorin, in the presenceof water and a metal capable of forming both higher and lower chlorids, in such a manner as to form the higher chlorid which immediately reacts on the ore to form chlorids 0f the metals contained therein and-is itself reduced to the lower chlorid, treating the solution in such a manner as to reconvert the lower chlorid into the higher chlorid without permitting free chlorin to come into contact with any sulfur which may have separated, again submitting the ore to the action of the regenerated solution and so on continuously until the desired metals are full y extracted from the ore.

2. The process of treating sulfid ores which consists in submitting the ores to the action of chlorin, in the presence of water and a metal capable of forming both higher and lower chlorids, in such a manner as to form the higher chlorid which immediately reacts on the ore to form chlorids of the metals contained therein and is itself reduced to the lowerchlorid, removing the sulfur set free, treating the solution in such a manner as .to reconvert the lower chlorid into the higher chlorid, again submitting the ore to the action of the regenerated solution and so on continuously until the desired metals are fully extracted from the ore.

3. The process of treating sulfid ores whichv consists, in submitting the ores to the action of chlorin, in the presence of water and a metal capable of forming both higher and lower chlorid, removing thesulfur set free,

treating the solution in such a manner as to reconvertthe "lower chlorid into the higher chlorid, again submitting the ore to the action of the regenerated solution and so on continuously until the desired metals are fully extraoted'from the ore, treating the resuitant chlorid product with a metal which will combine with chlorin as a' 'sol uble chlorid and throw down the metals" previously existing as practically insoluble chlorids such as lead chlorid. z

4. The process of treating sulfid ores WhICh consists in submitting the ores to the action of chlorin, in the presence of water and a metal capable of forming both higher and lower chlorids, in such a manner as to form the higher chlorid whieh immediately reacts on the ore 'to form ChlOI'ldS'Of the metals contained there'inand' is itself reduced to the lower c'hlorid, removing the sulfur set free with the lower chlorir ls, separating the sulfur therefrom and treating the solution in such a manner as to reconvert the lower ,chl'orid into the higher chlorid,again submitting the ore to the action of the regenerated solution and so on continuously until the desired metals are fully extracted from the ore.

5. The process of treating sulfi d ores which. consists in submitting the ores tothe action of chlori'n, in the presence of water'and metal capable of forming both higher and lower ch orids, in'such a'man'n'er as to form the higher chlorid which immediately reacts on the ore to form chlorids of the metals contained therein and is itself reduced to the lower ch'lo'rid, removing the sulfur set free with the lower 'chlorids, separating the sulfur therefrom and treating the solution in such a manher as to reconvert the lower chlorid into the seaese higher chlorid again, submitting the ore to the action of the regenerated solution and so rid and throw down'the metals previously existingas practically insoluble chlorids such as lead chlorid.

' 6, The process of treating sulfid ores. which consists in sub rnittingthe ores to the action of chlori'n, in he presence -of water and a metal capable of forming both higher and lower chlorids, in such a manner as to form the'higher chlorid which immediately reacts on theoreto form ohlorids of the metals contained thereinfland is itself reduced to the 1o'wer ch1orid removing the sulfurset free,

treating the solu'tiongin such amanner as to v reconvert the lower chloridinto the higher chlorid,'again submitting {the ore. to the action of the regenerated, solution. and so .on continuously until the desired metals are fully extracted from. the ore, treating th sultant chlorid' product with a metal which will combine with chlorin as a solubleohlorid and throw down the metals previously e'xist'ing'as practically insoluble chlorids such as lead chlorid, then separating the metals thrown down by reconverting them into chlorid salts in the presence of but little water, separating the chlorid solution so pro-- duced from the practically insoluble salts and again but separately throwing down the metals from their chlorids by the addition of a metal having a greater aflinity for chlorin.

In testimony whereof we havehereunto set our hands in the presence of two subscribing witnesses.

HARRY BAKE-R. 7 ANDREW THOMAS SMITH. 

